> The caller that orchestrates the state changes is xenwatch_thread> and it takes a mutex. In our processing of Xenbus states we can take> the luxery of going to sleep on a mutex, so lets do that and

This is only the direct conversion of existing spinlock accesses inxenbus.c. However, in the course of converting from the legacyimplementation you stripped a couple more (in xen_pcibk_attach(),xen_pcibk_reconfigure(), and xen_pcibk_setup_backend()), andthose should now get re-added imo.